Mobile Bridge Inspection Unit (MBIU)

The Mobile Bridge Inspection Unit (referred as MBIU) is an Electro-mechanically driven Articulated Structure mounted on a vehicle (a truck) as an aid towards proper inspection of bridges or similar infrastructures by enabling an inspection team of 3-4 persons carrying instruments access to the underside of bridge decks over flowing rivers or gorges.
Utilization of Municipal Solid Waste (MSW) in Road embankment

About 65-75% of segregated Municipal Solid Wastes can be used for embankment construction.Leachate studies indicate that MSW is a non hazardous material as concentration of heavy metals is within the permissible limit.Typical design cross sections have been arrived for 3m and 5m height MSW embankment.
Patch Fill-Pothole Repair Solution for Bituminous Roads

Patch-fill solution is useful for faster filling of potholes in bituminous roads without causing any environmental pollution and hindrance to roads users. Potholes filled by Path-fill shall be long lasting.
India hails success of first ‘steel-slag road’

A stretch of six-lane road experimentally paved with slag from steel-making in India has been shown to weather the beating from thousands of heavy trucks even though the surface is 30% shallower than that of roads paved with natural aggregates. Slag is made up of impurities melted out of the ore during the steel-making process. The trial, guided by the Central Road Research Institute (CSIR-CRRI) and sponsored by ArcelorMittal Nippon Steel (AM/NS).

CSIR-CRRI Bio-Bitumen Technology

A Sustainable Response to Bitumen Imports and Pollution due to Stubble Burning

This page presents a comprehensive technical overview of CSIR-CRRI’s bio-bitumen technology developed using pyrolysis of rice straw (parali) for sustainable flexible pavement construction.

National Context & Need Assessment India’s road construction sector is critically dependent on petroleum-based paving bitumen. Nearly 49% of the national bitumen requirement is met through imports, resulting in an annual foreign exchange outgo of approximately ₹25,000 crore. This dependence exposes the sector to global crude oil price volatility and supply-chain risks. At the same time, India generates more than 600 million tonnes of agricultural residue annually. A significant fraction of this biomass, particularly rice straw (parali), is burnt in open fields due to the absence of economically viable utilisation pathways, leading to severe air pollution, greenhouse gas emissions, soil nutrient loss and public health impacts. Addressing these challenges independently has yielded limited success. A convergent solution that simultaneously reduces bitumen import dependence and mitigates stubble burning is therefore essential for sustainable, resilient and environmentally responsible road infrastructure development.

Core Challenges

High dependence on imported petroleum bitumen
Escalating cost of flexible pavement construction
Environmental pollution due to open-field stubble burning
Loss of potential value from agricultural biomass

The CSIR Solution: Bio-Bitumen

CSIR-CRRI, in collaboration with CSIR-Indian Institute of Petroleum (IIP), has developed an innovative bio-bitumen technology using pyrolysis of rice straw. The resulting bio-oil is upgraded through chemical unit operations to produce a bio-binder suitable for flexible pavement applications, either as a partial replacement or as a modifier to conventional VG-grade bitumen.

Rice Straw → Pyrolysis → Bio-Oil → Bio-Binder → Flexible Pavements

Technology Process Overview

Pyrolysis of Rice Straw

Controlled thermal decomposition of rice straw produces bio-oil, bio-char and gaseous products.

Bio-Binder Production

Rice straw is densified into pellets and processed through pyrolysis to obtain bio-oil, which is further upgraded into a bio-binder suitable for flexible pavement applications.

Application in Pavements

Bio-binder is used in hot mix asphalt with conventional equipment and practices.

SARA Analysis (Chemical Characterisation)

Asphaltenes

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Performance Evaluation (Laboratory)

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Field Demonstration

A bio-bitumen trial section was successfully constructed on 26 October 2024 on the NH-6 (Jorabat–Shillong Expressway), demonstrating satisfactory field performance under traffic.